The photo below was actually taken in 19 exposures. I first focused on the closest foreground point and minutely stepped the focus for each subsequent shot a miniscule amount to the rear until the entire composition was covered. Later the images were combined, or "stacked", in a program called Helicon Focus to make one super-sharp image. You can download a high resolution image using the link below the photograph.
For this sequence I relied on a Nikon D800 to provide the maximum resolution required for making large prints. The lens was a 60mm macro set to f/5.6, a combo I find works best for this type of project.